Recipe from: Baking Illustrated
* Butter should be cold but not too cold- let it sit out at room temperature for 15-20 minutes to soften just a bit ** If you don't have a bench scraper, put the butter between two sheets of plastic wrap, and pound it with a rolling pin. You may also freeze half of the unbaked croissants for up to two weeks. Simply freeze before proofing, and when you're ready to bake, allow them to come to room temperature and proof as normal. (though they may need a few more minutes.)